CONCLUSION :

From the experiment we can say that the rotational speed of turbine, n, increase proportionally with input head, Hi, and torque,, but decreased proportionally with volume flow rate, Qv. We can also say that the rotational speed of turbine, n, proportionally sinusoidal with hydraulic input power, Ph, brake power, Pb, and turbine efficiency, Et. The theoretical data has a small different value with the experimental value because of equipments error.DISCUSSION :

From our observation of the experiment result, it was found that the input head, Hi, increased due to the decreasing of turbine rotational speed. The increasing of input head is around the interval of 0.1 to 0.5 meter. It is found that the volume flow rate, Qv, remain its value proportional to the turbine rotational speed, n, then decreasing slightly when the value of n is lower than 100Hz.The result of turbine efficiency, Et, shows an increment due to the decreasing of turbine rotational speed, n. Also, the torque,increased due to the decreasing of turbine rotational speed as well as input head, Hi. We also can see from the result that the hydraulic input power, Ph, increased for a while and then decreased at the end of the result. The result of brake power, Pb, shows that it increased and decreased alternately. All the data we got were from the computer. But from the theoretical calculation, we found small different value compared with the computer data. We assume that the errors were come from the sensor of equipments. As we know before, these equipments had some problems.1)The model of the radial flow reaction turbine which is connected to the computer system is used to run the experiment. Lab assistant showed how to use the machine.2)The machine is switched on; knob is used to adjust the brake force until we got the required steady value as shown on the monitor.3)When the value of brake force is steady, the value of volume flow rate, inputhead, hydraulic input power, torque, brake power and turbine efficiency measured by computer will be taken.4)The brake force is increased by adjusting the knob.5)The procedures of 3 to 4 are repeated until we got the table of graph.6)We can get the required value calculated by the computer automatically.Flow in a curved path.Pressure gradient and change of total energy across the streamlines.Velocity is a vector quantity with both magnitude and direction. When a fluid flows in a curved path, the velocity of the fluid along any streamline will undergo a change due to its change of direction, irrespective of any alteration in magnitude which may also occur. Considering the streamtube (shown in fig. 6.22),

Figure 6.22:as the fluid flows round the curved there will be a rate of change of velocity, that is to say an acceleration, towards the centre of curvature of the streamtube. The consequent rate of change of momentum of the fluid must be due, in accordance with Newtons second law, to a force acting radially across the streamlines resulting from the difference of pressure between the sidesBCandADof the of the streamtube element.In Fig. 4.2, suppose that the control volumeABCDsubtends an angleat the centre of curvatureO, has lengthsin the direction of flow and thicknessbperpendicular to the diagram. For the streamlineAD, let r be the radius ofcurvature, p the pressure and v the velocity of the fluid. For the streamlineBC, the radius will ber+r, the pressurep+pand the velocityv + v, wherepis the change of pressure in a radial direction.From the velocity diagram,Change of velocity in radial direction,v = v Or since = s/r,Radial change of velocity=v s/rbetweenABandCDMass per unit time flowing=mass density x area x velocitythrough streamtube= x ( b x s ) x vChange of momentum per unit=mass per unit time x radial change oftime in radial directionvelocity=brv s/r..6.33this rate of change of momentum is produced by the force due to the pressure difference between facesBCandADof the control volume:force =[(p + p) p ] bsequating equations (6.33) and (6.34), according toNewtons second law,pbs = brvs/rp/r = v/rfor an incompressible fluid, will be constant and equation (6.35) can be expressed in the of the pressure head h. sincep = gh, we havep = gh.Substituting in equation (6.35),pg h/r = v/r,h/r = v/gr,or, in the limit as r tends to zero,rate of change of pressure head in radial direction= dh/dr = v/gr(6.36)to produce the curve flow shown in Fig. 6.22, we have seen that there must be a change of pressure head in a radial direction. However, since the velocity v along the streamlineADis different from the velocityv + valongBC, there will also be a change in the velocity head from one streamline to another:rate of change of velocity head radially:= [(v + v) - v] / 2gr= v/g x v/r, neglecting products of small quantities,= v/g x v/r, as r tends to zero. .(6.37)in streamlines are in a horizontal plane, so that changes changes in potential head do not occur, the change of total headH i.e. the total energy per unit weight in a radial direction,H/r, is given by,H/r= change of pressure head + change of velocity head.Substituting from equations (6.36) and (6.37), in the limit,Change of total energy with radius,dH/dr = v/gr + (v/g) x (dv/dr)dH/dr = v/gr + (v/g) x (dv/dr)(6.38)the term(v/r + dv/dr)is also known as the vorticity of the fluid.In obtaining equation 6.38, it has been assumed that the streamlines are horizontal, but this equation also applies to cases where the streamlines are inclined to the horizontal, since the fluid in the control volume is in effect weightless, being supported vertically by the surrounding fluid.If the streamlines are straight lines,r = anddv/dr = 0. From equation (6.38) for a stream of fluid in which the velocity is uniform across the cross-section, and neglecting friction we havedH/dr = 0and the total energy per unit weightHis constant for all points on all streamlines. This applies whether the streamlines are parallel or inclined, as the case of radial flow.